Shield for detonators which are used in shot-firing in mines of all kinds and in quarries.



A. PRICE & W. PRYSE.

SHIELD FOB DETONATORS WHICH ARE USED IN SHOT FIRING IN MINES OF ALL KINDS AND IN QUARRIES.

APPLICATION FILED DEC. 12, 1911.

Patented Dec. 31, 1912.

Tl dTATEd PATENT @FFECE.

SHIELD FOR DETONATORS Specification of Letters Patent.

WHICH ARE USED IN SHOT-FIRING IN MINES or ALL KINDS AND IN aoaan ns.

Patented Dec. 31. 1912.

Application filed December 12, 1911. Serial No. 665,343.

To all whom it may concern:

Be it known that we, ABRAHAM PRICE, timberman, of 10 Sunny Bank, CWmpark, Treorky, Pontypridd, Glamorgan, England. and lVILLiAM Parse, colliery fireman, of 41 Vicarage Terrace, CWmpark, Treorky, Pontypridd. Glamor-gen. England, have invented new and useful Improvements in Shields for Detonators Which are Used in Shot-Firing.

in Mines of all Kinds and in Quarries; and we do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part hereof.

This invention has reference to detonators for use in shot firing in mines and quarries and has for its object to, provide means which obviate the possibility of the detonator becoming detached from the firing wire while being placed in position or withdrawn after Inisfire and thus insure safety during the operations of charging and ramming shot holes, withdrawal of the detonators in the case of misfire, and re-insertion of fresh detonators into the charge.

With this end in view our invention consists in providing means in addition to the usual fastening for gripping the firing wires at a short distance from the back of the usual fastening and in securing the Wires in such a manner that no tension can be exerted upon the length of firing wire intermediate the two tastenings. in this manner the strain exerted when withdrawing the detonator will betaken up Wholly by the rear fastening and not as hitherto, by the usual connection where the wire enters the back of the detonator.

in order that our invention may be readily understood and carried into etfect we will now proceed to describe the same fully for which purpose reference is to be had to the accompanying drawings in which Fig. 1 illustrates a vertical section through one form of device embodying our invention and Fig. 2

same.

Fig. 3 is a fragmentary view of a further modified form of the invention.

in carrying our invention into practice the is a slightly modified form of the said supporting means may comprise an extension at tht back of the detonator hereiu-' after more fully referred to or it may com prisc a tubular shield a of suitable material A modifications may preferably copper and ot' a size adapted to readily receive the detonator t). The end a of said shield a is closed as shown in the drawings and is provided with a hole r through which the firing'wires ii are adapted to pass. The opposite end of the shield a is serrated as at e and the body of the shield a is provided with apertures which in the torn] illustrated in Fig. l are shown as comprising holes f to admit of the charge being fired.

The wires (Z having been formed into a knot g are threaded through the hole (2 the ends being attached to the detonator t). The wires are then pulled up until the knot which is waxed jams against the closed end a'bf the shield a as shown in Fig. l the serrated ends (2 of the shield being turned inward so as to confine the detonator h with- -in the shield as shown by broken lines in Fig. 1 said detonator being thus supported and held in position by the waxed knot g.

In the slightly, modified form of device illustrated in Fig. 2 instead of providing the shield 11 with circular holes ,t' we provide slots h and two or any suitable number of the partitions between said slots it in the body of the shield are out free at the upper end and then turned slightly outward forming spring tongues i so that when the shield with its deto'natorlocated therein has been inserted in the casing of the cartridge said spring tongues i will engage with the can tridge case and prevent the shield and its detonator being displaced when the tube usedtor insertion of the shield into the car tridgc is withdrawn. The spring tongues Z are of suliicient strength to etiect this purpose but are yet fragile enough to collapse it a pull of about 10 pounds is applied to the wires in case it is necessary To withdraw the detonator owing to mistire.

if desired the form of shield shown m Fig. 1 may also be provided with spring catches similar to those illustrated in Fig. 2 by punching them out of the wall of the shield and in suitable position.

It will be seen that under our invention we have provided means whereby any tension on the firing wires will be taken up hetween the knotand the shield and this is an essential feature or the invention "which is not limited to the pre i e form of roustruction herein shown and described as many he made in the ame Without departing from the spiritand scope of the invention, for instance instead of constructing the shield of copper we may make the shield of some combustible but fiameless material or material of a very low melting point which would not obstruct the escape of gases from the detonator to the charge. Our shields can also be constructed so as to form an extension of the detonator casing and be substituted for or used in combination with the thin copper tube now used by the deto nator makers. or the cylindrical portion of the shield may be integral with the detonator casing. When the shields are in-the form of an extension of the detonator casing or combined with the thin copper tube now used by the detonator makers or is an integral part of the casing the end a of same is, during manufacture formed cylindrical instead of closed and with a serrated edge. Two of the points constituting part of the serrated edge are provided with holes 7. each of sutlicient diameter to permit one of the wires (Z passing through and the knot g having been tied a short distance from the usual fastening. the wires are then threaded separatel through each hole, the slack portion tuc (ed in and the serrations turned over to close the end of the casing as shown in Fig. 3. It will be obvious that although the kn otting of the wires as above described is the simplest way of attaining the object in view we may provide a clip of suitable construction and material in lieu of the knot adapted to be attached to the wires.

Any suitable and known form of clip may be used a preferred kind being formed of a short wire link given a twist to form a loop at each end through which the wires .attached to the deto-nator can be threaded and given half a turn bringing the wires to the center on each side. The clips may be fixed in position by wax.

It will be seen that by the use of our improved device perfect protection is assured against tiring the cap by friction upon the withdrawal or reinsertion thereof in the case of mistire while owing to the provision of the waxed knot which becomes wedged in the end of the shield the wires cannot become disconnected from the detonator. The dctonator being effectually supported by the shield can never become lost even should a fall occur due to pressure or the firing of another shot in the immediate vicinity:

lVhat we do claim as our invention and desire to receive by Letters Patent is 1.- A detonator of the character described comprising a tubular shield adapted to re ceive the detonator proper, firing wires passing through an opening in the end of said shield, means to prevent the withdrawal of said firing wires from said shield, means to permit the firing of the charge through said shield, and means engaging the base of the detonator to prevent a displacement of the shield and detonator, substantially as described.

2. A detonator of the character described, comprising a tubular shield adapted to receive the detonator proper, firing wires passing through a hole in the end of saidshield, a waxed knot connecting the firing wires to prevent the withdrawal of the same from said shield, openings within the tubular shield to permit the firing of the charge, and tongues engaging the base of the detonator to prevent a displacement of the shield and detc-nator, substantially as described.

3. A detonator of the character described comprising a tubular shield closed at one end and having serrated edges at its opposite end turned inwardly adapted to receive and hold the detonator proper, firing wires passing through a hole in the closed end of said shield, means connecting the firing wires within the shield to prevent their withdrawal therefrom, tongues integrally formed with the Wall of said shield to prcvent a displacement of the shield and deto-' nator, and means to permit the firing of a charge through said shield.

t. A detonator of the character described comprising a casing for the reception of the detonator proper. an extension of said casing having serrated edges turned inward, holes within said edges to allow the passage of the firing wires, :1 waxed knot connecting said firing'wires within said extension, and means to permit the firing of a charge through said shield and its cxten sion,substantially as described.

In testimony whereof we aflix our signatures in presence of two witnesses.

ABRAHAM PRICE. \VILLIAM PRYSE.

\Vitnesscs:

Vitamin D. liEES, Fmannmcx Jons Monet-ix. 

